John a



(No Model.)

J. A. CALDWELL. STAIR BBVBLING INSTRUMENT.

No. 495.300. Patented Apr. 11, 1893..

WITNESSES:

A TTORNE Y8.

UNrren STATES PATENT Orrton.

JOHN A. CALDWELL, OF VANCOUVER, CANADA.

STAlR-BEVELING INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 495,300, dated April 11, 1893.

Application filed $eptember 10, 1892. Serial No. 445,481. (No model.)

To all whom it may concerm Be it known that 1, JOHN A. CALDWELL, of Vancouver, British Columbia, Canada, have invented a new and Improved Stair-Beveling Instrument, of which the following is a full, clear, and exact description.

The invention relates to instruments for scribing stair curves, such as shown and described in the Letters Patent of the United States, No. 211,132, granted to me on January 7, 1879.

The object of the present invention is to provide a new and improved stair beveling instrument, which is simple and durable in construction, and adapted to be readily and conveniently adjusted and manipulated for drawing the desired lines.

The invention consists of blades provided with slotted transverse guideways, and sleeves engaging the compass legs and held transversely adjustable in the said guideways, the said sleeves being also mounted to turn in the guideways.

The invention also consists of certain parts and details, and combinations of the same, as will be hereinafter described and then pointed out in the claims.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a plan view of the improvement. Fig. 2 is an enlarged longitudinal section of part of the same on the line 2-2 of Fig. 1;

and Fig. 3 is a transverse section of the same on the line 3-3 of Fig. 1.

The improved stair beveling instrument is provided with the two compass legs A and B, jointed at C and of a suitable length, and pointed at their outer ends, as plainly indicated in Fig. 1. From the jointed end of the compass leg B extends a pointer D, engaging and indicating on a graduated segment E, fixed to the other compass leg A and having its center in the center of the pivot C. On the compass legs A and B are fitted to slide the sleeves F and F, respectively adapted to be secured in place on the said legs by set screws G, G screwinginthe sleeves and abutting onto the respective compass leg A or B. The sleeves F and F are fitted to slide transscrew K fits in an enlarged recess formed on the under side of the respective blade, so that the said head does not project and consequently forms no obstruction for conveniently moving the respective blade I or I, as will be readily understood by reference to Figs. 2 and 3. The aperture F in each sleeve F or F is made elongated as clearly indicated in Fig. 3, so that the respective compass leg can readily pass through the aperture, at the same time permitting the respective compass leg to rest on the top edges of the guideways so as to bind thereon when the screw G is pressed down. As shown in the drawings, the sleeves F and-F are made in the shape of hubs so as to turn within the guideways. It will be seen that by this construction, the blades I and I can be conveniently moved along the compass legs A and B, and the sleeves through which pass the compass legs can be readily transversely adjusted, at the same time permitting shifting of the blades with the respective sleeve as a center.

For further information as to the manner of using the instrument, see my aforementioned patent No. 211,132.

Having thus fully described my invention, I claim as new and desire to secure by Letters Patent 1. A stair beveling instrument, comprising jointed compass legs, a blade held adjustable on each compass leg, each blade being provid ed with a slotted transverse guideway, and a hub held adjustable in the said guideway and engaging the respective compass leg, substantially as shown and described.

2. In a stair beveling instrument, the combination, with jointed compass legs, of a sleeve formed with an elongated aperture for the passage of the respective compass leg, a set screw for fastening the sleeve and compass ted guideway engaged by the said sleeve, and I0 a screw for fastening the said sleeve to the said blade, substantially as shown and described.

JOHN A. CALDWELL.

Witnesses: I

G. F. UPHAM, G. B. FISHER. 

